1. Field of the Invention
The present invention relates to an apparatus and method of transmitting and receiving a wake-up signal so as to operate an ultra-low power sensor node, and more particularly, an apparatus and method of transmitting and receiving a wake-up signal by operating a radio frequency (RF) receiving unit for a predetermined amount of time repeatedly according to a predetermined time period to first check whether a signal received is a wake-up signal (before fully operating) so that power consumption required to receive the wake-up signal can be reduced.
2. Description of the Related Art
Generally, the life span of a plurality of sensor nodes used in a wireless sensor network is determined according to power consumption. In order to solve a high power consumption problem that may occur in the sensor nodes, various technologies related to a wake-up signal have been suggested. In conventional technologies related to a wake-up signal, the sensor nodes are in a sleep mode, and a radio frequency (RF) receiving unit that is always in a wake-up mode monitors for a wake-up signal and when a wake-up signal is detected, the mode of the sensor nodes is transited to an active mode in which the main operating unit of the sensor nodes are activated. In this case, the sensor nodes of which the mode is transited to the active mode request packet transmissions of neighboring nodes, and when data reception is completed, the mode of the sensor nodes is transited to the sleep mode again, and the RF receiving unit restarts wake-up signal monitoring.
In the conventional technologies related to a wake-up signal, all portions of a RF receiving unit are always in a wake-up mode and thus, there is a limit in realizing reduced power consumption.